Dog Tumors & Cancer in 2025: Vet-Backed Guide 🐾🩺

By Dr. Duncan Houston BVSc

📌 What Is a Tumor?

Tumors are abnormal growths from cells that divide uncontrollably. They can be benign (stay localized) or malignant (spread to other tissues).

🧠 Common Types of Dog Tumors

• Skin lumps: Lipomas (benign fat tumors) and mast cell tumors.
• Oral/oral cavity tumors: Epulides (benign), oral melanoma, squamous cell carcinoma, fibrosarcoma (malignant).
• Nasal tumors: Often adenocarcinomas or sarcomas.
• Testicular tumors: Common in unneutered males (e.g., Sertoli, Leydig cell tumors).
• Visceral tumors: Hemangiosarcoma (blood-vessel cancer), thymoma, intestinal leiomyoma, myocardial tumors.
• Brain/spinal tumors: Meningioma and peripheral nerve sheath tumors.

👀 Signs to Watch For

• New lumps or swellings that persist or grow
• Changes in skin—ulceration, bleeding, itchiness
• Oral issues—bad breath, drooling, difficulty eating, bleeding
• Respiratory signs—coughing, nasal discharge
• Systemic signs—weight loss, lethargy, decreased appetite

🔍 How Vets Diagnose Tumors

• Physical exam and fine-needle aspirate or biopsy
• Bloodwork and urinalysis for general health
• Imaging: X‑rays, ultrasound, CT/MRI to check size and spread
• Thoracic imaging for staging, especially with malignant types

💊 Treatment Options

• Surgical removal: Most common for localized tumors (lipomas, epulides, testicular, mast cell, oral masses)
• Radiation or chemotherapy: Used for aggressive types (mast cell, nasal tumors, oral melanoma)
• Targeted drugs: Tyrosine kinase inhibitors (e.g., for mast cell tumors)
• Supportive care: Pain management, antihistamines for mast cell tumors, fluids

📈 Prognosis by Type

• Benign tumors: Excellent prognosis with removal.
• Lipomas/histiocytomas: Often harmless or resolve spontaneously.
• Mast cell tumors: Variable; grade I–II often cured; III poorer prognosis.
• Oral tumors: Melanoma is highly aggressive; SCC and fibrosarcoma are moderately aggressive.
• Visceral tumors: Hemangiosarcoma—poor prognosis; surgical + chemo extends life slightly.

🛡️ Prevention & Early Detection

• Regularly check your dog’s entire body—including mouth, under skin folds, and testicles
• Follow spay/neuter recommendations to reduce risk (e.g., mammary/testicular tumors)
• Maintain routine vet checkups and discuss any changes
• Biopsy or aspirate new lumps early to determine the nature
• Encourage a healthy lifestyle: balanced diet, weight control, sun protection for light-skinned dogs

📞 When to See the Vet Immediately

• New lump that’s growing or bleeding
• Oral masses affecting eating
• Sudden collapse, collapse, pale gums (could signal internal bleeding)
• Persistent cough, nasal discharge, or unexplained lethargy

Early diagnosis and treatment are essential. Use the Ask A Vet app anytime for quick professional guidance 📱.

🛍️ Supportive Care

To support your dog during and after treatment, explore gentle supplements and comfort items, including healing chews.